The invention relates to a brake with a torque-measuring device, especially for elevators, wherein the brake, for example a shoe brake, has brake levers with brake shoes and wherein measuring elements of the torque-measuring device are connected with the brake levers.
Brakes with torque detection enable the generation of a counteracting torque of the drive motor by the amount of the measured torque, whereby the resulting torque at the brake shaft is equal to zero, so that the elevator can set off in jerk-free manner, thus without a torque jump, after release of the brake.
A torque-measuring shoe brake, which comprises measuring elements connected with the brake levers, has become known by German Patent Specification DE 37 07 276. The brake shoes are pivotably arranged at the brake levers by means of a rotary shaft, wherein the rotary shaft is mounted in the brake shoes by way of roller bearings. The rotary shaft is connected with one end of the measuring element, which measures the torque and which is so fastened by its other end to the brake lever that it forms a lever, the end of which connected with the rotary shaft is movable within narrow limits. Arranged at the opposite side of the shaft of the lever-like measuring element are strain gauge strips which, during measuring, produce a signal which is added to the signal delivered by the other brake lever. These signals are further processed and evaluated in such a manner that the brake is released only when the torque resulting from the loading is zero.
As the above-described device for measuring the torque consists of a number of interacting mechanical parts, the device is correspondingly relatively costly and complicated, which causes higher costs and can unfavorably influence the accuracy of the torque measurement.